Impact detonating fuze with arming delay



Dec. 13, 1960 2,963,974

IMPACT DETONATING FUZE WITH ARMING DELAY I Y. SEKELLA 2 Sheets-Sheet 1Filed May 9, 1958 Dec. 13, 1960 Y. SEKELLA 2,963,974

IMPACT DETONATING FUZE WITH ARMING DELAY Filed May 9, 1958 2Sheats-Sheet 2 Illl III I I .36 II "III I I 1 5 57 42 I as $1 I i In WWITNESS IMPACT DETONATING FUZE WITH ARMIN G DELAY Youston Sekella,Elmira, N.Y., assignor to The Bendix Corporation, a corporation ofDelaware Filed May 9', 1958, Ser. No. 734,145

4 Claims. (Cl. 10284) The present invention relates to an impactdetonating fuze with arming delay and more particularly to such a fuzeincorporating a mechanical time delay mechanism.

Impact detonating missiles to be launched by mortars as presentlyconstituted are not fully protected from premature explosion due to theforces engendered by the discharge of the mortar. It sometimes happens,therefore, that the set back or launching force causes detonation of themissile as soon as it clears the muzzle of the mortar with consequentjeopardy to the adjacent personnel.

It is an object of the present invention to provide a novel impactdetonating fuze which incorporates means for positively preventing thearming of the fuze for a predetermined time after the missile leaves themortar.

It is another object to provide such a device in which the delaymechanism is in the form of a gear train and escapement device whichcontrols a positive stop for the arming device.

-It is another object to provide such a device in which the initiatingmechanism is arranged to hold the primer out of operating position untilthe firing pin is moved to its armed position, whereby no amount ofrough handling, set-back or impact forces can cause premature explosionof the missile.

Further objects and advantages will be apparent from the foregoingdescription taken in connection with the accompanying drawings in which;

Fig. 1 is a vertical substantially mid-sectional view of a fuzeincorporating a preferred embodiment of the invention, some of the partsbeing shown in elevation in the interest of clarity, the parts beingshown in the positions assumed when the fuze is armed;

Fig. 2 is a sectional detail taken substantially on the line 2-2 of Fig.1;

Fig. 3 is a detail in perspective of the nose member of the fuzemechanism;

Fig. 4 is an enlarged substantially mid-sectional detail of the fuzeshowing the primer mechanism and the firing pin in the normal safe ordisarmed position;

Fig. 5 is a view similar to Fig. 4, showing the positions of the partsafter the missile has left the mortar, during the time delay periodprior to the fuze becoming armed, and

Fig. 6 is a detail of the escapement mechanism for delaying arming ofthe fuze.

In Fig. 1 of the drawing, there is illustrated the body 1 of a fuzewhich is provided with a lateral passageway 2 in which is slidablymounted a carrier member 3, which holds an explosive primer cartridge 4in a central location when the fuze is armed. A spring 5 urges thecarrier 3 toward its armed position as here illustrated.

The body 1 is formed with a socket 6, which is internally threaded forthe reception of a threaded extension 7 of a nose member 8, which servesto carry the timing and initiating assembly. A cup-shaped striker 9 isslidably and rotatably mounted in the nose 8, and is formed with anoutwardly extending projection 11 slidably re- 2,963,974 Patented Dec.13, 1960 ceived in an internal axially extending groove 12 in the nose.

As best seen in Fig. 2, the axially extending groove 12 intersects anarcuate groove 13 which extends around the interior of the nose andterminates at an enlargement forming a seat 14 for the reception of theprojection 11 when the fuze is in the disarmed or safe condition.

Yielding means are provided for rotating the striker 9 to move theprojection 11 from the safety position designated by A in Fig. 2 to theother end of the groove 13 as shown at B, and then for projecting thestriker 9 from the nose 8 until the projection 11 occupies the positionC in Fig. 2. As illustrated in Fig. 1, this means comprises a torsionspring 15 anchored at one end as shown at 16 to the striker 9 and at itsother end as shown at 17 to a partition member 18, which is fixedlymounted in any suitable manner in the nose member 8. This isaccomplished as illustrated by means of a cupshaped gear casing member19 anchored in the threaded extension of the nose 8 by a lock ring 20and having one or more tongues 22 forced into inclined keyways 23 formedin the periphery of the partition member 18. Said yielding means alsopreferably includes a compression spring 24 located between theprojecting end of the striker 9 and the partition member 18.

A firing pin 25 is fixed at one end in the striker 9 as indicated at 26and extends axially through the partition member 18 and gear case 19into position to engage and initiate the primer 4 when the primer is inarmed position and the striker 9 is depressed or strikes the target.

Means are provided for retarding the rotation of the striker 9 in thenose 8 to delay the arming of the fuze for a predetermined time afterthe projection 11 is released from its seat 14 by the set-back force asthe missile is launched. For this purpose the firing pin 25 is formedwith a non-circular cross section and an annular planet carrier 27having a conforming central opening is slidably mounted thereon so as torotate therewith. Pins 28 mounted in the carrier 27 provide bearings fora plurality of planets 29 Which mesh exteriorly with an orbit gear 31formed in the interior of the gear case member 19. The planets also meshwith a sun gear 32 which is journalled on the firing pin 25. The sungear 32 has fixedly mounted thereon an escapement wheel 34 which, asbest shown in Fig. 6, engages a plurality of pallets 35 mounted foroscillation on bearing pins 36 fixed in the base of the gear casing 19.Rotation of the sun gear 32 thus causes oscillation of the pallets 35,whereby the rotation of the sun gear is controlled.

The slide 3, which carries the primer 4, is provided with an opening 37into which the point 38 of the firing pin 25 projects when the missileis in disarmed condition as shown in Fig. 4. Rotation of the slide isprevented by suitable means such as a guide-pin 39 engaging in alongitudinal slot 41 in the slide.

Means are preferably provided for normally holding the slide in aretracted position. As shown in Fig. 4 this means is provided in theform of a laterally removable pin 42 which traverses a bifurcatedportion of the slide 2 and engages the slide at the base of thefurcations. This pin may be removed manually prior to loading themissile, or may be automatically ejected incident to the discharge ofthe missile from the mortar.

A safety wire 43 traversing the upper end of the nose 8 is arranged toengage in an opening 44 in the striker 9 to hold the striker in disarmedposition.

In operation, the safety pin 43 is first removed, and the missile isthen placed in the mortar.

When the missile is launched, the set-back or accelerational forcecauses the projection ll of the striker 9 to be moved out of its seat14, which permits rotation of the striker to be initiated by the spring15. The speed of this rotation is governed by the escapement mechanism29, 32, 34- and 35, whereby the projection 11 does not reach theposition 8 in Fig. 2 at the intersection of the circumferential groove13 with the axial groove 12 until a predetermined time after the missileleaves the mortar.

During this time the engagement of the point 38 of the firing pin 25within the opening 37 of the slide, as shown in Fig. 5, prevents theslide from bringing the primer 4 into alinement with the firing pin,

After the elapse of the time delay above provided, projection 11 of thestriker 9 enters the axial slot 12, and the striker is then projectedinto its armed position as shown in Fig. 1 and at C in Fig. 2 by thecombined action of the springs 15 and 24. At the same time, thewithdrawal of the firing pin 25 from the opening 37 of the slide permitsthe spring 5 to place the primer 4 in operative position whereby thefuze is fully armed. Consequently, when the striker 9 is depressed as onthe target, the firing pin 25 is driven into the primer, initiating theexplosion of the missile.

Although certain structure has been shown and described in detail, itwill be understood that changes may be made in the form and arrangementof the parts Without departing from the spirit of the invention.

I claim:

1. In an impact-detonating fuze for mortar shells, a nose member, astriker slidably and rotatably mounted in the nose member and projectingforwardly therefrom when the fuzc is armed, means normally retaining thestriker in retracted position comprising means to release the strikerafter a predetermined rotation of the striker in the nose, yieldingmeans for rotating and projecting the striker, gear and pallet meansmounted in the nose and operatively engaging the striker for controllingthe rate of rotation of the striker to delay its projection from thenose, a firing pin fixedly attached to the striker, and p ment with thefiring pin, and including means retaining the primer out of alignmentwith the firing pin until the striker is projected into armed position.

3. In an impact detonating fuze, a nose member, a striker rotatably andslidably mounted in the nose memher and having extended and retractedpositions, said nose member having an internal arcuate grooveintersected at one end by an internal axial forwardly extending grooveand having a forwardly extending enlargement at its other end, and anoutwardly extending projection on said striker loosely slidable in saidgrooves and normally seated in said enlargement when said striker is inthe retracted position, yielding means operatively engaging said strikerand actuated by launching acceleration forces for rotating the strikerto cause said projection to traverse the arcuate groove and forthereafter moving the striker axially in the forward direction to theextended position while said projection traverses the axial groove inthe nose member; a firing pin fixed to the striker, a primer movableinto and out of the path of travel of the firing pin, means engageablewith the firing pin for holding the primer out of said path until thestriker has been moved to its advanced position, and means for retardingthe rotation of the striker in the nose comprising an escapementmechanism driven by rotation of the striker in the nose.

4. An impact-detonating fuze as set forth in claim 3 in which saidyielding means urges the striker in its retracted position in thedirection to hold the projection of the striker in said enlargement ofthe arcuate groove.

References Cited in the file of this patent UNITED STATES PATENTS1,665,666 Junghans Apr. 10, 1928 1,975,809 Teitscheid Oct. 9, 19342,014,393 Mathsen Sept. 17, 1935 2,131,037 Brayton Sept. 27, 19382,709,962 Funk June 7, 1955 2,850,979 Hardwick Sept. 9, 1958 FOREIGNPATENTS 16,503 Great Britain 1914

